The Audio Research LS-2 is a modern tube line-stage preamplifier built around a simple, high-current circuit. It uses two 6H30 dual-triode tubes in a pure Class-A, zero-feedback design, with a single gain stage and cathode-follower topology. The result is a preamplifier focused on low noise, low output impedance and a clean, direct signal path.
 
The LS-2 takes the basic philosophy of Audio Research's original LS2 line stage and updates it with a modern control system, balanced connectivity and optional DAC and phono modules. It is designed as a dedicated analog preamplifier, while giving owners the option to add digital and vinyl playback capabilities later.
 
Pure Class-A Tube Design
At the heart of the LS-2 are two 6H30 tubes. The circuit operates in pure Class A with no negative feedback. The 6H30 is capable of delivering considerably more current than many traditional small-signal tubes, allowing the LS-2 to maintain a very low output impedance.
 
The cathode-follower output stage provides a 10-ohm balanced output impedance, making the LS-2 well suited to driving a wide range of power amplifiers and long interconnects.
 
Balanced and Single-Ended Connectivity
The LS-2 provides both balanced XLR and single-ended RCA connections. Gain is 12dB through both balanced and single-ended outputs, while the 25kΩ input impedance is the same for both connection types.
 
The preamplifier has been designed around a straightforward signal path rather than a large number of processing functions. Both balanced and single-ended outputs are available for flexible system configuration.
 
Modern Touchscreen Interface
Audio Research replaces the traditional collection of front-panel controls with a full-color touchscreen. The display provides input selection and naming, volume and balance adjustment, display intensity control and color selection.
 
The display also uses the same general typeface associated with Audio Research's Reference GhostMeters, giving the LS-2 a visual connection to the company's higher-end electronics.
 
Optional DAC and Phono Modules
The LS-2 can be expanded with optional plug-in modules. The DAC module adds USB, coaxial and optical digital inputs, allowing the preamplifier to serve as the digital front end for a two-channel system.
 
An optional phono module supports both moving-magnet and moving-coil cartridges. It provides 42dB of gain for MM cartridges and 62dB for MC cartridges.
 
The modular design allows the LS-2 to be configured around the sources actually used in a system rather than requiring external components for every function.
 
Key Features
• Pure-tube line-stage preamplifier
• Pure Class-A operation
• Zero-feedback circuit design
• Single gain stage
• Cathode-follower topology
• 2 × 6H30 dual-triode tubes
• 12dB gain, balanced and single-ended
• Balanced XLR and single-ended RCA connectivity
• 25kΩ balanced and single-ended input impedance
• 10Ω balanced output impedance
• 225Ω single-ended output impedance
• Full-color touchscreen interface
• Input naming and display customization
• Balance control
• Machined-metal remote control
• Optional DAC module with USB, coaxial and optical inputs
• Optional MM/MC phono module
• MM phono gain: 42dB
• MC phono gain: 62dB
• Hand-built in Minnesota